Side lift spreaders are commonly used for handling empty containers. Two horizontal telescopic beams allow containers of varying size to be handled by one spreader. Each telescopic beam is provided with a container locking device, commonly a twist lock or a lifting hook, that should mate with corner castings in the upper corners of the container. A main frame of the spreader holds the telescopic beams. The main frame is supported by and slidable in a guide cradle. The guide cradle is, in turn, held by a main carriage which is connected to a lifting device, such as a truck. Thus, the entire spreader and the container are movable by lifting along a mast of the truck. A common type of side lift spreader is shown in EP 0 701 964.
Empty containers may be stacked on top of each other on rather high container stacks. In recent years it has become common to use stacks of heights up to nine regular containers, which corresponds to 22.5 metre high stacks. It is difficult for the operator of the truck to control the position of the container and/or the spreader at such high levels. In particular it is difficult for the operator of the truck to align the locking device of the spreader with the with corner castings of the container at high levels. Moreover the mast may tend to flex somewhat at high levels which further render control of the spreader more difficult.
There is a need for an improved side lift spreader which in particular is suitable for lifting and handling empty containers at high stacks.